well, it's kinda odd - i have 2 media devices - dvd burner and cd burner. Both on on controller ( i think they are " cable select" ). Each of them works all right separately - i can burn disks, read disks - no problem.

the problem appears when i try to play dvd and burn cdrom ( actually blank full ).

there are no messages in /var/log/messages and top reports almost 0 activity .

I can't play dvd while the burner works....

Any ideas why and how to check what is wrong ?

// this is fedora 5 ... I 'm starting disliking this 5th version more and more..

Did this work in other versions of Fedora and or linux distributions?
Is DMA enabled for both drives? Check using the hdparm command.

By definition master/slave devices share the bus and so I/O entensive operations like what you are trying to do will naturaly have trouble since basicaly only one device can talk at a time.

Do you know the specifications of the motherboard. i.e. ultra DMA etc.

don't know if it worked before - this is a fresh install:
[root@fc ~]# hdparm -d /dev/hdc

/dev/hdc:
using_dma = 1 (on)
[root@fc ~]# hdparm -d /dev/hdd

/dev/hdd:
using_dma = 1 (on)

[root@fc ~]# ls -l /dev/dvd
lrwxrwxrwx 1 root root 3 Sep 6 06:41 /dev/dvd -> hdd
[root@fc ~]# ls -l /dev/cdrom
lrwxrwxrwx 1 root root 3 Sep 6 06:41 /dev/cdrom -> hdd

but :
[root@fc ~]# cat /proc/ide/hdc/model
LITE-ON LTR-52246S
[root@fc ~]# uptime
19:03:00 up 1 day, 12:21, 1 user, load average: 0.34, 0.45, 0.32
[root@fc ~]# cat /proc/ide/hdd/model
_NEC DVD_RW ND-3550A

[root@fc ~]# uptime
19:03:00 up 1 day, 12:21, 1 user, load average: 0.34, 0.45, 0.32

hmm. what it switched the drives again after reboot??? WTHell ?

Have you done the same thing with other versions besides FC5? IMO if you really want this to work you should put the drives on different controllers.

How are the drives physically connected i.e. which is hdc hdd? What is the make / model is your motherboard?

That's a very interesting topic you are bringing up.
why do i have to have them on a different controllers ? Is it a speed restriction?

As i mentioned earlier:
[root@fc ~]# cat /proc/ide/hdc/model
LITE-ON LTR-52246S
[root@fc ~]# uptime
19:03:00 up 1 day, 12:21, 1 user, load average: 0.34, 0.45, 0.32
[root@fc ~]# cat /proc/ide/hdd/model
_NEC DVD_RW ND-3550A
Where LTR is a CDRW burner and NEC is a DVD Dual Layer burner.

I have these drives connected the same way on RH9 and FC4, BUT i never used the simultaneously, plus it was on the old box, which is gone already.


How do i find out the motherboard model ?

another interesting thing i've noticed is that iostat does not report any activity on the hdc / hdd drives even thenthough the burning process is writing a whole disk .. Odd.

If the drives are switching devices then you could have a bad cable.

Read my first post.

Quote:"
By definition master/slave devices share the bus and so I/O entensive operations like what you are trying to do will naturaly have trouble since basicaly only one device can talk at a time."

well, i'm not sure if writing a cdrom should casue a whole bus to be "locked" for extensive periods of time, that any other device can't get access to the bus. Also i would think that writing to the hard disk ( say copy a huge file ) should be more resource demending job than copying to/from slow cdrom... Please let me know what am i missing..

any other thoughts?